Overview

Students finish their study of the great of the web by learning about two top-level protocols, HTTP and also DNS. The lesson begins with a review of the great students have already learned, namely the physical Internet, IP, and also TCP / UDP. The lesson climate dives right into the main point of the unit i m sorry is "What happens once I kind an deal with into my browser?" student will finish two quick activities, one unplugged, and one plugged, that check out how the DNS works. Students climate watch videos explaining exactly how both DNS and HTTP work, acquisition notes in a detailed activity guide. The great concludes with a testimonial of exactly how the different layers of the web work.

You are watching: How does dns help the internet scale

Purpose

This class is designed come wrap up the collection on how the net works and highlight the main architecture philosophies that openness, reliability, and scalability. However, actions taken by governments and organizations an obstacle some that these architecture philosophies and also may hinder the capability of the World broad Web come be important worldwide. College student will begin thinking about some the the dilemmas caused by this conflicts, which they will discover further ~ this lesson.

Agenda


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Objectives

Students will be may be to:

explain how HTTP is used for share the files and also pages that consist of the World vast Web define how the Domain Name system helps the internet scale by allowing devices to discover the IP addresses associated with a domain name describe how various layers that protocols ~ above the Internet develop upon and also rely ~ above one another

Preparation


Preview the version of the net Simulator supplied in this lesson. Girlfriend can easily practice using this version v a solitary browser window and no partner.

Lesson Modifications

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Attention, teachers! If you room teaching virtually or in a socially-distanced classroom, please read the complete lesson arrangement below, climate click right here to accessibility the modifications.


Showing the need for DNS: This quick unplugged task helps students know why the DNS exists in the an initial place. With devices joining the net all the moment it"s difficult for each device to save track the each various other device"s IP address.


Keep it Short: This task can be done very quickly, commonly in about 3 minutes, prior to students begin to check out the main point challenge. If students begin running far from girlfriend that"s a an excellent sign they"ve checked out what renders this activity tricky!


Distribute: together students enter course hand each of them a solitary IP address (precut by teacher native IP deal with Labels - Teacher Resource)


Today we"re walking to end up our research of the layers of the Internet and learn about two final protocols. Let"s simply hop ideal in!


When you walked right into the room i handed each of you a on slide of paper. This is your IP address. We know that in order to interact on the web you require to recognize the IP deal with of the other computer. So far we"ve let you ask one another"s addresses when interacting on the internet Simulator, but this deserve to be tricky.


Do This: your goal is to produce a perform in her journals of every one of your classmates IP addresses. The just rules:

You might walk around the roomYou may share info with classmatesYou may talk / share details with just ONE classmate at a time
Devices are joining and also leaving the web all the time. IP addresses don"t stay constant. If you go to a coffee shop or restart your browser your an equipment might it is in assigned a new IP address.If IP addresses room switching, it"s really hard because that each computer system to keep an accurate list.It would make much more sense if there were one device that preserved track that all that information.

Circulate: together students room working, circulate quietly with the room.

Approach a student and silently take their IP attend to slip away from them.Give that human a new IP deal with slip (or a re-used IP address).Repeat the above two procedures as many times together you can, as you circulate the room.

Prompt: talk about with your classmates the complying with prompts

Why do you think ns was convert IP addresses?If IP addresses can change, is over there a better way for anyone to know everyone else’s IP address?

Discuss: talk about responses come these inquiries with students, utilizing the discussion goal to guide the conversation.


If we desire the web to range up come billions of devices, climate we require a better way to figure out one another"s IP addresses!


Activity (30 mins)

DNS - video clip - 8 mins

Prompt: as we watch the following video clip take notes on:

How does the DNS solve the trouble of translating domain names prefer example.com into IP addresses?How go the DNS help the net scale?

Display: show The Internet: IP Addresses and also DNS - video clip on DNS, which describes how the works. Video will automatically start playing at the development of DNS.


The DNS is a network the servers that track the IP addresses of various domain names prefer example.comWhen girlfriend visit a website you first ask the DNS for the IP resolve of the domain you desire to visit. The an initial server to ask may need to ask other servers for this information. This system allows billions of gadgets to get included to the network there is no putting push on any type of one computer or server to understand all the IP addresses in the world.

Prompt: comment on the adhering to prompts v a partner:

How go the DNS resolve the problem of translating domain names favor example.com right into IP addresses? how does the DNS aid the net scale?

Discuss: have actually students discuss responses with their partners, climate share out with the class. Focus on the key takeaways in the discussion goal.

DNS - net Simulator - 12 mins


Wrapping up the internet Simulator: This should serve as a to solve conclusion to students" usage of the internet Simulator. Students should notice the adhering to things


You should speak through the DNS in bespeak to acquire the IP resolve of her classmateYou have to send a separate messageThey may notification that packets are now numbered favor in the TCP protocol from critical class


Previewing HTTP: While no explicitly around HTTP, there are countless similarities between this task and exactly how HTTP works. In both instances a computer makes a inquiry over the internet in level text (e.g. Acquire ....) that then it s okay a response. You may make those connections later after students have actually watched the video about HTTP.


Let"s go gain on the internet Simulator one last time to see how all the different pieces we"ve learned about will to the right together.


Do This: Log into this version of the internet Simulator

No talk at all, not also to gain your partner’s IP addressAsk the DNS for the IP attend to of a user through sending gain usernameUse the IP address you get ago to interact with at the very least 2 friends. You deserve to talk about: In her ideal people what time would school start? or What would certainly you eat for her perfect meal?

As we have the right to see right here on the internet Simulator, thanks to the DNS we can talk to other human being even if us don"t know their IP addresses. Additionally, this system is developed entirely on all the other layers below it. As soon as you talk to the DNS you"re still sending info over the network, friend still require to recognize the IP attend to of a DNS server, and also you tho send a article that it s okay turned right into packets and also routed utilizing UDP (or periodically TCP) and also IP.


HTTP and also the World wide Web - 10 mins


Discussion Goal


Goal: right here are the most important points for students to take it away around HTTP and the means it works


When girlfriend visit a website you"re actually obtaining sent a paper by a server. HTTP is resolving the problem of how to ask for that file.Your computer and also that server connect using a protocol referred to as HTTP. HTTP is plain-text, so that literally includes the ASCII indigenous "GET ..." and also the document name requested.All that your communications are being sent over the internet so this requests are being sent out inside TCP/IP packets and also over the physics wires that the Internet.There are various other secure ways of sending information online because using HTTP, all our details would otherwise be sent out as plain text.Certificate authorities ensure that when you start a secure link you"re talking to the website you think you"re talk to.

We"ve gained our heads wrapped approximately how DNS works. Let"s learn around the last item of the puzzle here, a protocol called HTTP. In this video we"ll find out what happens once you in reality visit a website and the language supplied to send those papers around.


Do This: together we clock this video clip take notes on the HTTP protocol.

What difficulty is HTTP solving?What is a gain request and what are your requesting?How walk HTTP rely on the other layers the the Internet?Why space SSL/TLS, and HTTPS necessary?What do certificate authorities do and why are they necessary?

Display: watch the video about HTTP.

Prompt: evaluation these questions with a partner about HTTP

What difficulty is HTTP solving?What is a obtain request and also what are your requesting?How walk HTTP count on the various other layers that the Internet?Why are SSL/TLS, and also HTTPS necessary?What carry out certificate authorities do and also why are they necessary?

Discuss: have students share the end their responses with the course to make sure students understand the an essential takeaways about HTTP.


Goal: usage this final conversation to evaluation not simply this lesson yet every protocol / layer of the web students have actually learned so far. You"d aim to see responses choose the complying with


When you kind in bromheads.tv.org, your web browser will contact the DNS to find bromheads.tv.org"s IP addressWhen you obtain the deal with you"ll send an HTTP gain request to bromheads.tv.org come send you its homepagebromheads.tv.org"s server will respond through the HTML password that makes up its web pageAll that the communications over happen ~ above the web which way TCP or UDP will certainly break the message into packets and then send them. If TCP is used, error checking will occur.IP will route the packets back and forth in between your computer and the serverAll the this information is sent over the physics wires, cable, wifi networks, and routers that comprise the physics network of the internet.

Journal: evaluation the an essential takeaways the the lesson and also have student add new vocabulary to your journals: scalability, DNS, World vast Web, HTTP

Distribute: provide students a copy the the layers of the internet - task Guide

Prompt: utilizing your great of the Internet task guide to help you, explain how every of the different layers is involved when you go to a connect like bromheads.tv.org?

Discuss: usage this final prompt as a testimonial of whatever covered in both today"s lesson and also those that come before. You"ll actually probably want to begin with the bottom of your testimonial guide.


At this allude you all know a LOT an ext about the web then the mean person. Morning we"re walking to rotate our attention to thinking through exactly how we have the right to use this understanding to make great decisions around the Internet"s influence on our day-to-day lives.

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Assessment: check For Understanding

Check For expertise Question(s) and solutions can be uncovered in every lesson on bromheads.tv Studio. This questions have the right to be supplied for an departure ticket.

Question: pick the two statements that ideal describe the relationship in between HTTP and the World broad Web

Question: In your own words explain the following around the Domain surname System

What trouble does the DNS solve?How go the DNS assist the world vast web scale so the billions of customers can accessibility billions of internet pages?